[Drug dependence tests on a new anesthesia inducer, midazolam]

Area of Science:

• Pharmacology
• Neuroscience
• Addiction Research

Background:

• Midazolam is an intravenous anesthesia inducer.
• Assessing drug dependence liability is crucial for understanding potential for abuse.
• Benzodiazepines vary in their dependence potential.

Purpose of the Study:

• To compare the drug dependence liability of midazolam and triazolam in male cynomolgus monkeys.
• To evaluate midazolam's potential for self-administration and withdrawal symptoms.
• To contrast midazolam's effects with triazolam and pentobarbital.

Main Methods:

• Self-administration studies using intravenous drug delivery under different reinforcement schedules (FR1, FR10, progressive ratio).
• Assessment of drug-initiated self-administration in naive animals.
• Evaluation of withdrawal sign suppression in physically dependent animals.
• Chronic administration studies followed by withdrawal sign observation and antagonist challenge.

Main Results:

• Midazolam and triazolam maintained self-administration at lower doses than pentobarbital under FR1 and FR10 schedules.
• Midazolam showed weaker self-administration maintenance in progressive ratio tests compared to triazolam.
• Midazolam initiated self-administration in fewer naive animals than pentobarbital.
• Midazolam's ED25 for withdrawal suppression was similar to its CNS depression ED25, unlike triazolam and pentobarbital.
• Fewer withdrawal signs were observed after chronic midazolam administration compared to triazolam and pentobarbital.

Conclusions:

• Midazolam's drug dependence liability is within the range of most benzodiazepines.
• Midazolam appears to have a lower potential for drug dependence compared to pentobarbital.
• The study provides valuable data on the abuse potential of midazolam in preclinical models.